Conventional networks typically include data communications devices that transmit data packets from one or more sources to one or more destinations. Certain data communications devices, such as routers, receive packets containing data and control information at input ports, and, based on destination or other information included in the packets, route the packets to appropriate output ports that lead to either another router or to the packet's final destination.
Routers can be configured as having various sizes and capacities based upon their intended use. For example, low capacity routers are typically used in home networks to route data among three or four personal computers. High-performance routers, commonly used by enterprises such as telecommunication companies and Internet service providers, provide relatively high bandwidth packet routing and can process packets for many thousands of different end users.
High-performance routers can be complex devices that include multiple processors and other circuitry integrated into a single physical box. For example, a high-performance router can include physical interface cards, adaptors for holding the physical interface cards, a routing engine, and switching and forwarding adaptors. Each one of these components can be implemented on a separate circuit board controlled by one or more processors. These circuit boards can then be mounted in a single physical chassis to form the router.